Radiation thermometer comprising a heated measuring tip

ABSTRACT

The invention relates to an infrared thermometer, especially an ear thermometer for measuring temperature, comprising an infrared sensor, a measuring tip which can be heated by a heating element, an actuating device which can be operated by a user, a control device and a display device. The invention also relates to a method for measuring temperature, especially by means of a radiation thermometer having a heatable measuring tip. Said control device switches off the heating element after the user has actuated an actuating device. After a certain amount of time, a plurality of temperature measurements are successively carried out, and the temperature to be displayed is determined from said measured temperatures or an error message is generated. At the latest, after a maximum measuring time has elapsed or after a maximum number of temperatures have been measured, the temperature to be displayed or an error message is displayed on the display device.

[0001] The invention relates to a radiation thermometer comprising a heated measuring tip, especially an infrared thermometer for measuring temperature. Such thermometers are known to contain an infrared sensor, an ambient temperature sensor and an evaluating device which determines the temperature of a measurement object from the output signals of the sensors.

[0002] An infrared ear thermometer comprising a measuring tip which can be heated by a built-in heating element is known from WO 00/58703. If a heated measuring tip is inserted in an auditory canal, almost no more heat exchange takes place between the measuring tip and the auditory canal so that the measuring tip and the auditory canal are in thermal equilibrium during the temperature measurement. In this way, measurement errors which arise as a result of cooling of the ear canal if the measuring tip inserted in the ear canal is cooler than said canal, are avoided. The ear thermometer is provided with a control device for regulating the temperature of the measuring tip which also determines whether the measuring tip is located in the auditory canal and switches the heating element on or off when the measuring tip is inserted in the auditory canal or withdrawn therefrom.

[0003] An infrared thermometer is known from EP 1081475 whose measuring tip can be heated at its anterior end by a heatable infrared sensor arranged there.

[0004] The object of the invention is to provide a radiation thermometer comprising a heatable measuring tip and a method of measurement for such a thermometer which allows the same simple operation as is known from thermometers without a heatable measuring tip.

[0005] In order to solve this object, a thermometer according to the invention is provided with a device for controlling the measuring sequence. In a preferred embodiment of a thermometer according to the invention the control device and the evaluating device are combined in a microcontroller or the like which also controls a display device. The measuring sequence is independent of whether the measuring tip is heated directly by a heating element or indirectly by a heatable infrared sensor.

[0006] The measuring sequence according to the invention is described in the following. The user will first switch on the thermometer in an inherently known fashion. The measuring tip of the thermometer is then heated automatically to a specific temperature, for example, to approximately 37° C. This temperature is achieved in a very short time, for example, a few seconds, in a thermometer having a structure known from WO 00/58703 or EP 1081475. The thermometer is thus ready for measurements. The user can now insert the measuring tip of the thermometer into the ear and start the temperature measurement by actuating an actuating device, for example, by pressing a button.

[0007] The thermometer according to the invention can also contain a detecting device which establishes whether the measuring tip of the thermometer is inserted in the ear or not. In this case, the insertion of the measuring tip into the ear can be equated to the actuation of the actuating device, i.e., after insertion the detection device will establish that the measuring tip is located in the ear and thereupon start the further measuring process without the user needing to additionally actuate a (further) actuating device.

[0008] With a battery-operated thermometer, it is especially advantageous if the thermometer automatically switches itself off, for example, after 1 minute in order to save current if the user has not yet actuated the actuating device by then.

[0009] After the user has actuated the actuating device, with an infrared thermometer according to the invention a measuring process takes place automatically in the following fashion: first, the heating of the measuring tip is switched off. Preferably after a certain time has elapsed, for example 1 second, the temperature of the measurement object, i.e., especially the body temperature, is measured several times. This delay in the measuring sequence has the advantage that any temperature differences which may be present in the measuring tip or the infrared sensor can be equalised before the temperature measurements. The temperature of the measurement object to be displayed is then determined from the measured temperatures and at the latest after a maximum measurement time has elapsed or after a maximum number of temperature measurements, is displayed on a display device. However, if the measured temperatures differ too much from one another or a minimum number of successively measured temperatures are not at least approximately the same or do not settle down to a specific value in the course of the measurement process or another suitable criterion for the validity of the measured temperatures is not satisfied, it is advantageous if an error message is output instead of a temperature, which recommends that the user repeats the temperature measuring process. The error message can be output after a minimum measuring time or a minimum number of temperature measurements if a valid temperature value can no longer be expected within the maximum measuring time or after the maximum number of temperature measurements. However, if the measured temperatures do not differ too much from one another or a minimum number of successively measured temperatures are at least approximately the same or settle down to a specific value in the course of the measurement process or another suitable criterion for the validity of the measured temperatures is satisfied, the temperature to be displayed is preferably displayed immediately, i.e. before the maximum measuring time has elapsed or before the maximum number of temperature measurements.

[0010] In a preferred embodiment of the thermometer according to the invention, during the current temperature measurements a signalling device is activated by the control device, for example, in the form of a flashing light-emitting diode and/or a series of beeps which indicates to the user that the measuring process is completed, for example, by the light-emitting diode being lit continuously and/or a long-drawn-out beep. In this way it should be prevented that the user withdraws the thermometer from the ear before the entire measuring process has been completed.

[0011] An advantageous embodiment of the thermometer according to the invention also has a data storage device and the above-mentioned signalling device by which means the data stored in the data storage device can be output, for example, the measured temperatures, the displayed temperatures, the total number of measuring sequences carried out or the like. For this purpose the flashing of the light-emitting diode or the beeping is coded in a specific fashion so that this data can be recorded by an external reader, decoded, further processed and/or displayed. 

1. An infrared radiation thermometer, especially an ear thermometer for measuring temperature, comprising an infrared sensor, a measuring tip which can be heated by a heating element, an actuating device which can be operated by a user, a control device and a display device, characterised in that the control device switches off the heating element after the user has actuated the actuating device, after a certain time has elapsed, carries out a plurality of temperature measurements one after the other, determines the temperature to be displayed from the measured temperatures or generates an error message, and at the latest after a maximum measurement time has elapsed or after a maximum number of temperature measurements, displays the temperature to be displayed or an error message on the display device.
 2. The thermometer according to claim 1, characterised in that the control device determines a criterion for the validity of the measured temperatures and then displays the temperature to be displayed if the criterion is satisfied or after a minimum measurement time or after a minimum number of temperature measurements, displays the error message if the criterion cannot be expected to be satisfied within the maximum measurement duration or after a maximum number of temperature measurements.
 3. The thermometer according to claim 1 or claim 2, characterised in that it also has a signalling device which can be controlled by the control device which signals the sequence and/or the end of the temperature measurements to the user.
 4. The thermometer according to claim 1 or claim 2, characterised in that it also has a data storage device and a signalling device and that the data stored in the data storage device are output by means of the signalling device.
 5. The thermometer according to claim 1 or claim 2, characterised in that it also has a detection device which can determine whether the thermometer is inserted in the ear or not.
 7. A method for measuring temperature by means of a radiation thermometer comprising a heatable measuring tip, especially an ear thermometer for measuring temperature, characterised in that after switching on the thermometer, a heating element is switched on which heats the measuring tip of the thermometer, after actuating an actuating device, the heating element is switched off, after a certain time has elapsed a plurality of temperature measurements are carried out one after the other, the temperature to be displayed is determined from the measured temperatures or an error message is generated, and at the latest after a maximum measurement time has elapsed or after a maximum number of temperature measurements, the temperature to be displayed or the error message is displayed on the display device.
 8. The method according to claim 7, characterised in that a criterion for the validity of the measured temperatures is determined and the temperature to be displayed is then displayed if the criterion is satisfied and after a minimum measuring time or after a minimum number of temperature measurements the error message is displayed if the criterion cannot be expected to be satisfied within the maximum measurement time or after a maximum number of temperature measurements.
 9. The method according to claim 7 or claim 8, characterised in that the sequence and/or the end of the temperature measurements is signalled to the user.
 10. The method according to claim 7 or claim 8, characterised in that the temperature measurements are only begun if a detection device has established that the measuring tip of the thermometer is located in the ear. 